Information of vehicle acceleration may be useful in various vehicle systems. For example, during antilock braking and acceleration slip control, information of vehicle acceleration can be used for identifying the road surface condition. However, the signal of vehicle acceleration, whether obtained from a chassis mount accelerometer or derived from vehicle speed measurement such as from a ground speed sensor or a nondriven wheel speed sensor during acceleration slip control is usually contaminated with noise. In order to remove the noise from the useful data, a low pass filter is usually used. However, using a conventional low pass filter also results in delay in the recognition of a sudden change in acceleration with a resulting delay in the control response to the vehicle acceleration change.
For example, vehicle acceleration may be used in estimating the road surface condition for traction and/or acceleration slip control. The delay associated with the conventional low pass filter will delay the system response to a transition in a road surface condition such as a shift between a low and a high road surface coefficient of friction. If the cutoff frequency of the low pass filter is increased, this time delay may be shortened, but poor data quality results at steady state conditions.